1. Albright, M. (2001). The right balance will secure NATO’s future (7 December 1998). In Institute for Security Studies (Ed.), Chaillot Papers (vol. 47). From St-Malo to Nice: European defence: Core documents (pp. 10–12).
2. BAE Systems, EADS, & Thales. (2003). Time to Act! Joint Declaration of BAE Systems, EADS and Thales. http://www.defense-aerospace.com/articles-view/release/3/17409/euro-majors-warn-%22it%27s-time-to-act%22.html
3. Barroso, J. M. D. (2011). The State of Europe—Die Europa Rede. Berlin. http://europa.eu/rapid/press-release_SPEECH-11-738_en.htm
4. BBC News. (2014, March 12). Poland and Baltics wary over Crimea. https://www.bbc.com/news/world-europe-26526053
5. Bergmann, J., & Niemann, A. (2018). From neo-functional peace to a logic of spillover in EU external policy: A response to Visoka and Doyle. JCMS: Journal of Common Market Studies, 56(2), 420–438. https://doi.org/10.1111/jcms.12608